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Jan 19, 2021 7 min read

How to tell the difference between male and female cannabis plants

author
by George Mouratidis
Cannabis plants

The cannabis plant isn’t unisex. Throughout most of its history, cannabis naturally evolved via sexual reproduction. It’s only in recent years that “sterile” techniques like cloning and tissue propagation have become industry standards.

CULTIVATION: Easily grow your own cannabis at home. All you need is seeds.

The reasons mainstream cultivators don’t pollinate cannabis are simple: males don’t produce big buds, and pollinated female plants focus their energy on producing seeds instead of quality buds. Only unpollinated female plants will reward growers with the resinous buds tokers enjoy. Thankfully, there are many simple techniques growers could use to spot pesky males before their pollen sacs burst. 

How to tell if a marijuana plant is male or female

There’s only one foolproof method to properly determine the sex of your cannabis plant: examine the nodes. At these junctures between the main stem and branches, you should see early signs of a male or female plant.

Male plants will grow ball-shaped pollen sacs, but females will have wispy white hairs. These thin hairs are called “pistils,” and they’re designed to catch pollen from male plants. Some plants will develop both pollen-sacs and pistils — these are hermaphrodites and must be treated as males (more on that later). 

Until you see the bright white pistils break through, it can be tricky to verify you’ve got a girl in your garden. However, male plants tend to “show their sex” well before females. So, if you notice these protrusions early in the vegetative stage, it’s more likely you have a male plant.

Read more about cannabis plant anatomy here.

It’s also worth mentioning that pollen sacs look similar to aces in a standard deck of cards. Female calyxes, however, typically have a narrower tip where the pistil will emerge.

As a side note: please don’t be alarmed when you see these pistils change color. In fact, you should be worried if your pistils don’t turn from white to amber. Pistils on all healthy cannabis plants will gradually darken as they mature.

When can you tell the sex of a marijuana plant?

There’s no set time when cannabis plants express male or female traits. However, you’ll probably notice the first signs of your plant’s sex just before flowering (about six weeks).

According to most cultivators, male plants develop quicker than female plants. Indeed, it’s not unheard of for pollen sacs to emerge within two to three weeks of vegetation. 

If you’re unsure what your plant’s gender is in the vegetative stage, please be careful before switching to a flowering light schedule. Once you flip the flowering switch, you will send the signal to any potential males that it’s time to pollinate. So, if you don’t catch a male plant quickly enough, you risk pollinating your plants.

Are there other ways to distinguish male vs. female marijuana?

The only sure-fire way to differentiate male vs. female marijuana is to look at the nodes. However, there are a few secondary gender indicators to be aware of.

For instance, some cannabis growers claim the stipules around a plant’s nodes have sharper edges on female plants. If these tiny leaves are more rounded, there’s a greater chance your plant is a male. Also, some gardeners say there are more stipules on females as opposed to males. Just bear in mind, there’s no science to support this “stipule theory.”

Another feature to examine is the main stem’s size. Typically, male plants have fatter stems than female plants. Plus, a few growers say male plants grow taller and have fewer fan leaves than females.

Can you tell a plant’s gender from cannabis seeds? 

cannabis seeds
Always avoid seeds that look green, feel squishy, or crack under gentle pressure. (Algirdas Gelazius/123rf)

Unfortunately, nobody can tell the gender of a cannabis plant just by looking at the seeds. All healthy cannabis seeds have the same traits (i.e., brown color with streaks of grey, a shiny exterior, and a firm feel). Always avoid seeds that look green, feel squishy, or crack under gentle pressure.

While you can’t determine a seed’s sex by its appearance, you can find many breeders that offer pre-sexed seeds. Plenty of seed banks now have feminized seeds that take the guesswork out of growing marijuana. As long as you grow these seeds in a reliable, low-stress environment, they should all express female traits during vegetation.

Anyone who purchases “regular seeds” must take extra time to analyze every plant’s nodes. In most cases, about 50 percent of seeds in an un-feminized batch will become males.

Are lab tests for cannabis gender legit? 

If you don’t want to wait for your weed’s nodes to appear, there is a quicker way to figure out your plant’s gender: order a cannabis lab test! Yes, many legitimate labs offer cannabis gender tests for curious cultivators. 

Simply send a seedling sample to your chosen lab and wait for the results. Typically, labs will accept leaf samples once your marijuana plant reaches two to three weeks old.

Even though gender testing is relatively new in the cannabis industry, it is legitimate if you’re working with a high-quality lab. It will cost a little extra for this test, but some cultivators say it’s money well spent.

What the heck is a hermaphrodite cannabis plant?

If your plant has gone hermaphrodite, you’ll most likely see both pollen sacs and pistils throughout your cannabis plant. (Shutterstock)

Interestingly, hermaphroditism isn’t all that uncommon in the cannabis kingdom. Even if you’re working with feminized seeds, you’ll probably notice a few cannabis plants “herm out” throughout your cultivation career.

If your plant has gone hermaphrodite, you’ll most likely see both pollen sacs and pistils throughout your cannabis plant. You might also see a distinctive “banana-shaped” pollen sac form over female flowers. Both of these conditions are clear signs your plant is a hermaphrodite.

Although hermaphrodite plants are technically male and female, you have to treat them as males. These plants still have plenty of pollen sacs that will burst during the flowering stage. To avoid pollinating your ladies, it’s best to remove hermaphrodites ASAP. Alternatively, you could carefully remove pollen sacs on hermaphrodites, but this technique is only recommended for expert cultivators.

So, why would a cannabis plant turn into a hermaphrodite? The leading theory is that hermaphroditism is a response to environmental stressors. If your plant feels it doesn’t have enough energy to receive pollen from males, it will create pollen sacs of its own. Therefore, the best way to avoid hermaphroditism is to maintain a stable, stress-free environment in your grow tent.

However, this doesn’t mean genetics have no impact on cannabis hermaphroditism. Certain strains (e.g., Gorilla Glue #4 and Blueberry) have a higher-than-average hermaphrodite risk. If you’re new to cannabis cultivation, it’s worthwhile reading a few growing forums to see if any of your favorite strains have hermaphrodite issues.

Can growers influence regular seeds to become female plants?

There’s no way to guarantee the gender of a regular seed, but some cultivators say the environment could influence a plant’s sex. Most significantly,cultivators believe unnecessary environmental stress will decrease the odds of females.

For the highest chance of growing female flowers, constantly monitor critical metrics like pH, temperature, and humidity. You might also want to experiment with shorter-than-average lighting schedules during vegetation. Some cultivators claim 16/8 or 14.5/9.5 lighting schedules increase the odds of females. Just remember these shorter lighting periods will make your plants grow at a slower rate.

On the subject of lighting, a few ganja gardeners argue grow lights with a blue spectrum might increase the odds of female plants. The theory is that the blue spectrum is as close to natural sunlight as possible, hence it’s less stressful on your seeds.

Disclaimer: Scientists have yet to confirm or deny any of these growing tips. While it’s always good practice to create a stable growing environment, there’s no guarantee any of these hacks will influence your seeds’ gender. 

Are there any uses for male marijuana plants?

Marijuana leaves in a trash can
Discarded marijuana leaves and plants (The Cannigma/Anthony Travagliante)

Males will always play second fiddle to feminized flowers. While male plants produce a few cannabinoids, they can’t compare with trichome-rich feminized buds. However, that doesn’t mean male plants are entirely useless.

Most significantly, male plants are essential for preserving the genetic legacy of the cannabis species. Sure, cloning can produce identical cannabis plants, but that’s not necessarily a good thing. Indeed, an overreliance on cloned cannabis might phase out “natural cannabis.” Anyone concerned about the genetic diversity of the cannabis species must continuously cross-breed males and females as nature intended.

But beyond breeding cannabis cultivars, gardeners say male cannabis plants have fantastic potential as a companion plant. Many male plants give off terpenes that could naturally repel nasty pests. So, if you grow veggies or fruits outside, it might be beneficial to plant male ganja plants nearby.

Lastly, since male cannabis plants have a great nutrient profile, many gardeners say they’re a fantastic addition to their compost. If you like to make mulch at home, consider adding your marijuana plant to the mix for an extra boost.

Never neglect the nodes – get your ganja’s sex right the first time

At first, you might find it challenging to tell male from female pot plants. However, as you begin to examine your plant’s nodes first-hand, you should have an easier time separating these two genders. Take some time to study pictures of male, female, and hermaphrodite plants to know what you’re looking for. As a final tip, invest in a pocket-friendly jeweler’s loupe to get a clear view of your plant’s potential pistils.

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